Physics

Problem

During a test run, a motor does work on a belt as follows: • from

t = 0

t = 2\,\text{s}

, the work done increases uniformly from

0

60\,\text{J}

; • from

t = 2\,\text{s}

t = 5\,\text{s}

, the work done increases uniformly from

60\,\text{J}

90\,\text{J}

. Determine the average power developed by the motor over the entire

0

5\,\text{s}

interval. a)

30\,\text{W}

12\,\text{W}

18\,\text{W}

20\,\text{W}